788 EXPERIMENT STATION EECORD. [Vol. 43 



ard formulas. The standard formula for the loss at entrance head 0.5H,, for the 

 type of opening for which the formula was developed ran both higli and low 

 in the tests, and may be considered as holding good as an average, so far as 

 any developments in the laboratory results are concerned. Friction loss in the 

 structure was indicated as being negligible in the larger sections of the tube 

 and was heaviest at the throat or contracted section. It was so small as to 

 be neglected in the results. The varied shapes of the discharge lip did not 

 seem to affect the total efficiency, and since all the models were of uniform 

 design at the intake end, nothing developed in the tests at that point or in the 

 bends from which to draw conclusions. 



The total efficiency for the various models for different air-inlet conditions 

 ran 0.84, 0.98, and 0.983 for the three sets of tests when grouped and averaged. 

 Similar tests on larger models, without the introduction of varying air-inlet 

 conditions, ran from 0.644 to 0.80.5, and in a number of other siphons in this 

 country and Europe coefficients of discharge ranging from 0.7 to 0.82 have been 

 found. 



With reference to the i-elation between the depth of submergence of the dis- 

 charge lip and the depth of water over the throat to bring the siphon into 

 action under different conditions of air inlet, the tests indicated a tendency to 

 develop a back pressure in the crown between the rise of the water surface at 

 the inlet and the suppressed effort of the air to escape imder the discharge lip 

 when the seal was complete. The placing of air inlets and the submergence of 

 the outlet end were found to be so closely related that the points are difficult of 

 separation. 



Data from other sources are also summarized. 



Irrigation investigations, G. E. P. Smith (Arhoiia Sta. Rpt. 191S, pp. 351- 

 358, figs. 2). — Irrigation investigations at the station for the year are sum- 

 marized, including data on the status of irrigation water supplies, pump irriga- 

 tion, cement pipe for irrigation pipe lines, and tractor power on farms. 



It is noted that in trials of reinforced cement pipe in all cases the reinforced 

 pipe were found to be weaker than plain pipe. 



Seepage and waste water losses on AVapato Irrigation Project, L. W. 

 Holt {Engin. News-Rec, 85 {1920), No. 8, pp. 365, 366, fig. i).— Measurements 

 of the flow from the discharge system of the Wapato Irrigation Project in 

 Washington are reported, which show that, as an average for the six years 

 from 1913 to 1919, about 60 per cent of the applied water reached the main 

 drainage ditch. On an average 3.7 acre-feet of the 6.1 acre-feet applied to each 

 acre were lost by deep percolation and through waste-water ditches, and at least 

 90 per cent of the, total loss was by deep percolation. 



Flood problems of Calaveras River, H. Baknes {Sacramento: Calif. Dept. 

 Engin., 1919, pp. 57, pis. 2, figs. 15). — This is a preliminary report on flood 

 control of the Calaveras River, with particular reference to the protection of 

 agricultural lands against overflow. It contains maps and data of a pre- 

 liminary survey. A comparison of a by-pass plan of flood control with that of 

 utilizing a reservoir indicated the latter plan to be the more feasible. 



The flow of water in drain tile, D. L. Yabnell and S. M. Woodward {U. S. 

 Dept. Agr. Bui. 85^ {1920), pp. 50, pis. 13, figs. 5). — This is a progress report of 

 an investigation being conducted on the carrying capacity of tile drains as con- 

 duits. The results of 824 separate tests are I'eported on commercial sizes of 

 clay and concrete tile varying from 4 to 12 in. in inside diameter. The capacity 

 at different depths of flow was also determined. For comparison, 69 tests were 

 made on 10 and 12-in. tile so laid as to closely approximate poorly laid drains 

 found in the field. 



